The present invention relates to intake manifolds and in particular to an intake manifold having an interchangeable center runner section.
Conventional intake manifolds used on V-block engines having dual cylinder bands are generally multi-purpose apparatus which include a coolant crossover section through which coolant is transferred from each engine cylinder bank to the centrally located thermostat outlet; a distributor boss on which the engine distributor is mounted; a center plate section for covering and sealing the engine valley between the cylinder banks to keep contamination from the engine's interior parts and to prevent the escape of pollutants into the atmosphere; a thermostat outlet housing; and a center runer apparatus coupling the carburetor to the intake ports of the cylinder transferring fuel and air from the carburetor to the cylinders. In order to alter the runner configuraton and carburetion of a conventional intake manifold, it is necessary to replace the entire intake manifold. Such a replacement requires the following steps:
1. draining the engine coolant, to prevent spillage into the engine valley;
2. removing all ignition wires;
3. disconnecting and removing the distributor cap and the distributor;
4. disconnecting the coolant hoses and the thermostat housing;
5. disconnecting the fuel lines and carburetor linkages;
6. removing the various brackets attached to the intake manifold including the steering columnar bracket, the alternator-generator bracket, the air conditioner brackets and, if present, the coil bracket;
7. loosen and remove all bolts attaching the intake manifold;
8. pry manifold off;
9. clean all surfaces, replacing all gaskets and then reversing the above steps.
The above procedure has at least two distinct disadvantages over and above the amount of time and effort required:
Firstly, the removal of the distributor necessitates a resetting of the engine timing.
Secondly, the removal of the entire intake manifold breaks the engine valley closure causing the loss of oil and exposure of vital internal parts of the engine to contamination. The installation of a new intake manifold requires that the engine valley seal be reformed to restore the integrity of the closure. Furthermore, most of the above operations are unnecessary to the objective of providing a new runner configuration and are only required because the coolant crossover, the distributor boss, the thermostat housing and the engine valley cover are integral with the runners.
The present invention obviates the above operations when it is desired to merely change the runner configuration by providing a novel intake manifold assembly having a novel isolated base member and a removable and interchangeable center runner member mountable to the isolated base member. More specifically, the base member has an engine valley cover which covers the engine valley from front to back and side to side to maintain the required engine valley closure; a coolant crossover section with a thermostat housing; a distributor boss section on which the distributor is mounted; and two port flange sections integrally formed on either side of the engine valley cover section between the coolant crossover section and the distributor boss section. The two integral port flange sections provided in accordance with the invention, eliminate the necessity of providing edge sealing surfaces and complicated edge sealing gaskets which would otherwise be necessary between the edges of the runner member and the adjoining edges of the base member. In the preferred embodiment each port section is relatively thin so that no permanent runner extension is incorporated. This allows maximum versatility in configuring the runners. Each port section has an upper mating face. The center runner member has oppositely disposed runner mating faces each of which is positioned and held adjacent to one of the port mating faces with a gasket therebetween.
In operation, the isolated base member of the invention is bolted to the engine between the respective engine cylinder banks thereby covering and sealing the engine valley. In the preferred embodiment the base member has a lower engine mating face which is substantially identical to that of a stock intake manifold. Hence, the stock intake manifold can simply be removed from an engine and the isolated base member of the invention bolted to the engine in its place.
The base member thus includes the coolant crossover section, an engine valley cover region for maintaining closure of the engine valley section, and a distributor boss section. A center runner member having any one of a number of runner or plenum configurations may then be selected and bolted to the base member without removing it. When it is desired to change the runner or plenum configuration and the associated carburetor, it is only necessary to remove and replace the center runner member. Thus, the base member remains in place eliminating the necessity of breaking the coolant crossover seals, breaking the engine valley closure, removing the distributor from the distributor boss thereafter necessitating a retiming of the engine, and removing the thermostat outlet housing. Indeed, the runner configuration of the invention may be quickly and easily changed by merely disconnecting and reconnecting a fuel line and the carburetor linkages.
If the base member is to be made from lightweight plastic, the invention also has the advantage of being in one piece without the necessity of using a plurality of molds to make a plurality of manifold pieces which must be glued together. Such a one-piece mold is possible because the complicated runner member is separate from the base member. It is particularly desirable that the base member port sections be as thin as possible to allow maximum space and hence maximum flexibility in designing runner member.
Various prior art patents illustrate multipiece intake manifolds. For example, multipiece manifolds are shown in U.S. Pat. No. 3,831,566 filed May 31, 1973, and issued to Thomas; and U.S. Pat. No. 3,994,129, filed Dec. 30, 1974, and issued to Sakurai, et al. However, neither of these patents provides an intake manifold wherein the intake manifold runners are separable from the remaining parts of the intake manifold to provide a base member which by itself provides engine valley closure, a coolant crossover with thermostat housing and distributor mounting boss.
Also known in the prior art is the engine configuration wherein the coolant crossover section and the distributor boss section are integral with the engine block rather than the intake manifold. In such an engine, the engine valley is considerably shortened in length and is between the cylinder banks on the sides and the coolant crossover section and distributor boss section on the ends. In this configuration, the intake manifold comprises a plate for enclosing the engine valley and a runner section which may be attached to the heads of the engine. Although this configuration allows some flexibility in interchanging runners, the engine block is considerably more difficult to cast because of the complexity added by the integral coolant crossover section and integral distributor boss section.